I think punches to the kidneys at the back should be ok, shouldnt turn your back on your opponent.
I'd LOVE to take you up on that hehe :boxing:
I am positive your mind will change quite quickly...
theres this thing called a brain stem back there, and if it gets too hard, you could be in for some serious problems. obviously there is no way in HELL that you box, otherwise you wouldnt of even thought to consider thinking of this question. try getting hit there with headgear on and even by someone who can barely punch, and see what happens to you, and then ask this question...